Background: Sorafenib and irinotecan (NEXIRI regimen) showed promising activity with a disease control rate (DCR) of 65% in heavily pretreated mutated (mt) KRAS metastatic colorectal cancer (mCRC) patients in a phase I/II trial (Samalin et al. 2014).This multicentre randomized phase II trial aimed to determine the 2-month progression-free survival rate (2-PFS) of NEXIRI versus irinotecan or sorafenib monotherapy in mtRAS mCRC patients after failure of all approved active drugs at the time of the study. Methods: Patients PS ≤ 1 with progressive measurable and non-resectable mtKRAS (then RAS) mCRC pre-treated with irinotecan, oxaliplatin, fluoropyrimidines and bevacizumab (none regorafenib), were randomized in 3 arms: NEXIRI (irinotecan IV 120 (C1), 150 (C2) and 180mg/m² (C3) if diarrhea grade < 1 in a biweekly regimen combined with a fixed dose of sorafenib, 400mg twice daily) versus irinotecan alone (180mg/m²) versus sorafenib alone until progression or toxicity, with cross over to NEXIRI at progression for the monotherapy arms. The primary endpoint was the 2-PFS (RECIST v1.1). Pharmacokinetic, pharmacogenetics and pathologic translational studies were undertaken.Results: We included 173 patients (median age 62 [31-82]; PS 0/1: 38/61%) between 2012/09 and 2014/07 in 17 French centres. Main results are shown below (median follow-up 17.5 months). Conclusions: We confirmed the NEXIRI regimen efficacy in a randomized study for refractory mtRAS mCRC patients. These results justify comparing this combination to regorafenib or TAS 102 monotherapies in this population. Ancillary studies are ongoing to identify biomarkers. Clinical trial information: NCT01715441

*170 patients **18 (6/4/8) non-evaluable patients.